System, method and controller for managing and controlling a micro-grid

Abstract

A system, method and controller for managing and controlling a micro-grid network. The system includes a plurality of energy resources including at least one dispatchable energy resource and at least one intermittent energy resource, wherein the at least one of the energy resources is an energy storage element and at least one of the intermittent energy resources is responsive to environmental conditions to generate power, a controller configured to record operational constraints of the energy resources, obtain an environmental condition prediction and generate a component control signal based on the environmental condition prediction and the operational constraints corresponding to the energy resources. The controller is further configured to receive a network disturbance signal and generate a dynamic control signal based on such disturbances.

We claim: 
     
       1. A method of controlling a micro-grid network, wherein the network includes a plurality of distributed energy resources including at least one dispatchable energy resource and at least one intermittent energy resource, wherein at least one distributed energy resource is an energy storage element and at least one of the intermittent energy resources is responsive to environmental conditions to generate power, the method comprising:
 providing a controller comprising a processor, a memory coupled to the processor and an adder, the memory having installed thereon a computer-executable code defining a steady state control module and a dynamic control module; 
 recording, in the memory, at least one operational constraint corresponding to each distributed energy resource; 
 receiving, by the processor, one or more system wide signals representative of a predicted change to the network, wherein the predicted change comprises an environmental condition prediction; 
 periodically generating, in a predetermined frequency, by the steady state control module, a component control signal for each distributed energy resource in a first set of distributed energy resources, including the energy storage element, based on the environmental condition prediction and the at least one operational constraint corresponding to the respective distributed energy resource, wherein the component control signal defines a steady state set-point for each distributed energy resource of the first set of the distributed energy resources; 
 receiving, by the processor, one or more network disturbance signals representative of a sudden change within the network; 
 selecting, by the dynamic control module, from the plurality of distributed energy resources, a second set of distributed energy resources having respective at least one operational constraints suitable to be engaged to address the sudden change within the network, the second set of distributed energy resources having at least the energy storage element and at least one other type of distributed energy resource in common with the first set of distributed energy resources; 
 dynamically generating, by the dynamic control module, a dynamic control signal for each distributed energy resource in the second set of distributed energy resources, based on the one or more network disturbance signals and the at least one operational constraint corresponding to the respective distributed energy resource to address the sudden change within the network, the dynamic control signal defining a set-point perturbation to the respective steady state set-points of each distributed energy resources in the second set of distributed energy resources; 
 combining, using the adder, the steady state set-point of each distributed energy resources in the second set of distributed energy resources generated by the steady state control module with the respective set-point perturbation of each distributed energy resources in the second set of distributed energy resources generated by the dynamic control module to generate an overall control signal; and 
 maintaining a voltage and a frequency of the network within a predetermined range with the overall control signal. 
 
     
     
       2. The method of  claim 1 , wherein the environmental condition prediction relates to a time period and the component control signals are generated for the time period. 
     
     
       3. The method of  claim 2 , further comprising:
 predicting a load demand for the micro-grid network to provide a total predicted load demand; and wherein generating the component control signal for each of the first set of distributed energy resources comprises generating the component control signal based on the total predicted load demand for the micro-grid network. 
 
     
     
       4. The method of  claim 3 , wherein the load demand is predicted in part based on the at least one environmental condition variable. 
     
     
       5. The method of  claim 2 , wherein the time period is selected from the group consisting of:
 a predetermined number of seconds; and 
 a percentage of a duty cycle of the energy resources. 
 
     
     
       6. The method of  claim 1 , wherein obtaining the environmental condition prediction includes receiving at least one environmental condition variable and generating the environmental condition prediction based on the at least one environmental condition variable. 
     
     
       7. The method of  claim 1 , further comprising:
 predicting a power generation level of intermittent energy resources in the micro-grid network based on the environmental condition prediction to provide a total predicted supply. 
 
     
     
       8. The method of  claim 7 , wherein the intermittent energy resource is a wind power generation system and the dispatchable energy resource is a diesel power generation system. 
     
     
       9. The method of  claim 8 , wherein the energy storage element is a battery. 
     
     
       10. The method of  claim 9 , wherein the component control signal generated for each of at least some of the distributed energy resource from the first set is selected from the group consisting of:
 a power switching signal to turn off the dispatchable energy resources, a charge/discharge signal to at least one energy storage element to charge the at least one energy storage element and a power level control signal to the intermittent energy resources to curtail supply to the micro-grid network in excess of total predicted load demand and power stored by the at least one energy storage element in the power network when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network and the total predicted wind power supply and the total predicted load demand in the micro-grid network are stable; 
 a power level control signal to the dispatchable energy resources to gradually decrease supply, a charge/discharge signal to at least one energy storage element to charge or discharge the at least one energy storage element based on the operational constraints of the dispatchable energy resources and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of the total predicted load demand and power stored by the at least one energy storage element in the micro-grid network when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply in the micro-grid network is stable and the total predicted load demand in the micro-grid network is increasing; 
 a power level control signal to the dispatchable energy resources to gradually decrease supply, a charge/discharge signal to at least one energy storage element to charge or discharge the at least one energy storage element based on the operational constraints of the dispatchable energy resources and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of the total predicted load demand and power stored by the at least one energy storage element in the micro-grid network when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply in the micro-grid network is stable and the total predicted load demand in the micro-grid network is decreasing; 
 a power level control signal to the dispatchable energy resources to gradually decrease supply, a charge/discharge signal to at least one energy storage element to charge or discharge the at least one energy storage element based on the operational constraints of the dispatchable energy resources and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of the total predicted load demand and power stored by the at least one energy storage element in the micro-grid network when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply in the micro-grid network is increasing and the total predicted load demand in the micro-grid network is stable 
 a power level control signal to the dispatchable energy resources to gradually decrease supply, a charge/discharge signal to at least one energy storage element to charge or discharge the at least one energy storage element based on the operational constraints of the dispatchable energy resources and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of the total predicted load demand and power stored by the at least one energy storage element in the micro-grid network when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply in the micro-grid network is increasing and the total predicted load demand in the micro-grid network is increasing; 
 a power level control signal to the dispatchable energy resources to gradually decrease supply, a charge/discharge signal to at least one energy storage element to charge or discharge the at least one energy storage element based on the operational constraints of the dispatchable energy resources and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of the total predicted load demand and power stored by the at least one energy storage element in the micro-grid network when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply is increasing and the total predicted load demand in the micro-grid network is decreasing; 
 a power level control signal to the dispatchable energy resources to gradually decrease supply, a charge/discharge signal to at least one energy storage element to charge or discharge the at least one energy storage element based on the operational constraints of the dispatchable energy resources and a power level control signal to the intermittent energy resources to maximize production when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply in the micro-grid network is decreasing and the total predicted load demand in the micro-grid network is stable; 
 a power level control signal to the dispatchable energy resources to dispatch required diesel, a charge/discharge signal to at least one energy storage element to charge the at least one energy storage element and a power level control signal to the intermittent energy resources to maximize production but to curtail supply to the micro-grid network based on the operational constraints of the dispatchable energy resources when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply in the micro-grid network is decreasing and the total predicted load demand in the micro-grid network is increasing; 
 a power level control signal to the dispatchable energy resources to gradually decrease supply, a charge/discharge signal to at least one energy storage element to charge or discharge the at least one energy storage element based on the operational constraints of the dispatchable energy resources and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of the total predicted load demand and power stored by the at least one energy storage element in the micro-grid network when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply in the micro-grid network is decreasing and the total predicted load demand in the micro-grid network is decreasing; 
 a power level control signal to the dispatchable energy resources to dispatch required diesel and a power level control signal to the intermittent energy resources to maximize production when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, and the total predicted wind power supply and the total predicted load demand in the micro-grid network are stable; 
 a power level control signal to the dispatchable energy resources to dispatch required diesel and a power level control signal to the intermittent energy resources to maximize production when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, the total predicted wind power supply in the micro-grid network is increasing and the total predicted load demand in the micro-grid network is stable; 
 a power level control signal to the dispatchable energy resources to gradually increase supply, a charge/discharge signal to at least one energy storage element to charge or discharge the at least one energy storage element based on the operational constraints of the dispatchable energy resources and a power level control signal to the intermittent energy resources to maximize production when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, the total predicted wind power supply in the micro-grid network is decreasing and the total predicted load demand in the micro-grid network is stable; 
 a power level control signal to the dispatchable energy resources to dispatch required diesel and a power level control signal to the intermittent energy resources to maximize production when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, the total predicted wind power supply in the micro-grid network is stable and the total predicted load demand in the micro-grid network is increasing; 
 a power level control signal to the dispatchable energy resources to dispatch required diesel and a power level control signal to the intermittent energy resources to maximize production when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, the total predicted wind power supply in the micro-grid network is increasing and the total predicted load demand in the micro-grid network is increasing; 
 a power level control signal to the dispatchable energy resources to dispatch required diesel and a power level control signal to the intermittent energy resources to maximize production when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, the total predicted wind power supply in the micro-grid network is decreasing and the total predicted load demand in the micro-grid network is increasing; 
 a power switching signal to the dispatchable energy resources to gradually stop supplying power and a power level control signal to at least one energy storage element to supply power to the micro-grid network when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, the total predicted wind power supply in the micro-grid network is increasing and the total predicted load demand in the micro-grid network is decreasing; and 
 a component control signal for at least some of the energy resources comprises generating a power level control signal to the dispatchable energy resources to dispatch required diesel and a power level control signal to the intermittent energy resources to maximize production when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, the total predicted wind power supply in the micro-grid network is decreasing and the total predicted load demand in the micro-grid network is decreasing. 
 
     
     
       11. The method of  claim 8 , wherein the energy storage element is a flywheel. 
     
     
       12. The method of  claim 11 , wherein the component control signal generated for each of at least some of the distributed energy resources from the first set is selected from the group consisting of:
 a power switching signal to turn off the dispatchable energy resources except the diesel power generation system with the lower power production and a power level control signal to the intermittent energy resources to curtail supply to the micro-grid network in excess of total predicted load demand when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, and the total predicted wind power supply and the total predicted load demand in the micro-grid network are stable; 
 a power switching signal to turn off the dispatchable energy resources except the diesel power generation system with the lower power production and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of total predicted load demand when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply in the micro-grid network is stable and the total predicted load demand in the micro-grid network is increasing; 
 a power switching signal to turn off the dispatchable energy resources except the diesel power generation system with the lower power production and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of total predicted load demand when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply in the micro-grid network is stable and the total predicted load demand in the micro-grid network is decreasing; 
 a power level control signal to the dispatchable energy resources to gradually decrease supply and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of total predicted load demand when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply in the micro-grid network is increasing and the total predicted load demand in the micro-grid network is stable; 
 a power level control signal to the dispatchable energy resources to gradually decrease supply and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of total predicted load demand when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply in the micro-grid network is increasing and the total predicted load demand in the micro-grid network is increasing; 
 a power level control signal to the dispatchable energy resources to gradually decrease supply and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of total predicted load demand when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply is increasing and the total predicted load demand in the micro-grid network is decreasing; 
 a power level control signal to the dispatchable energy resources to gradually increase supply and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of total predicted load demand when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply in the micro-grid network is decreasing and the total predicted load demand in the micro-grid network is stable; 
 a power level control signal to the dispatchable energy resources to gradually increase supply and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of total predicted load demand when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply in the micro-grid network is decreasing and the total predicted load demand in the micro-grid network is increasing; 
 a power level control signal to the dispatchable energy resources to gradually increase supply and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of total predicted load demand when a total predicted wind power supply in the micro-grid network exceeds the total predicted load demand in the micro-grid network, the total predicted wind power supply in the micro-grid network is decreasing and the total predicted load demand in the micro-grid network is decreasing; 
 a power level control signal to the dispatchable energy resources to dispatch required diesel and a power level control signal to the intermittent energy resources to maximize production when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, and the total predicted wind power supply and the total predicted load demand in the micro-grid network are stable; 
 a power level control signal to the dispatchable energy resources to dispatch required diesel and a power level control signal to the intermittent energy resources to maximize production when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, the total predicted wind power supply in the micro-grid network is increasing and the total predicted load demand in the micro-grid network is stable; 
 a power level control signal to the dispatchable energy resources to gradually increase supply and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of total predicted load demand when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, the total predicted wind power supply in the micro-grid network is decreasing and the total predicted load demand in the micro-grid network is stable; 
 a power level control signal to the dispatchable energy resources to dispatch required diesel and a power level control signal to the intermittent energy resources to maximize production when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, the total predicted wind power supply in the micro-grid network is stable and the total predicted load demand in the micro-grid network is increasing; 
 a power switching signal to turn off the dispatchable energy resources except the diesel power generation system with the lower power production and a power level control signal to the intermittent energy resources to maximize production but curtail supply to the micro-grid network in excess of total predicted load demand when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, the total predicted wind power supply in the micro-grid network is increasing and the total predicted load demand in the micro-grid network is increasing; 
 a power level control signal to the dispatchable energy resources to dispatch required diesel and a power level control signal to the intermittent energy resources to maximize production when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, the total predicted wind power supply in the micro-grid network is decreasing and the total predicted load demand in the micro-grid network is increasing; 
 a power switching signal to turn off the dispatchable energy resources when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, the total predicted wind power supply in the micro-grid network is increasing and the total predicted load demand in the micro-grid network is decreasing; and 
 a power level control signal to the dispatchable energy resources to dispatch required diesel and a power level control signal to the intermittent energy resources to maximize production when a total predicted load demand in the micro-grid network exceeds the total predicted wind power supply in the micro-grid network, the total predicted wind power supply in the micro-grid network is decreasing and the total predicted load demand in the micro-grid network is decreasing. 
 
     
     
       13. The method of  claim 1 , further comprising:
 operating at least some of the distributed energy resources, including the energy storage element, in response to the component control signal. 
 
     
     
       14. The method of  claim 1 , wherein at least one operational constraint corresponding to each distributed energy resource includes at least one operational constraint selected from the group consisting of a switching cycle constraint and a minimum load constraint. 
     
     
       15. The method of  claim 1 , wherein the component control signal corresponding to at least one of the distributed energy resource from the first set is selected from the group consisting of:
 a power switching signal, wherein the at least one distributed energy resource starts or stops supplying power to the micro-grid network in response to the power switching signal 
 a power level control signal, wherein the at least one distributed energy resource supplies power to a hybrid power grid in a quantity corresponding to the power level control signal; 
 a source charge/discharge signal, wherein the energy storage element in the micro-grid network charges or discharges in response to the charge/discharge signal; and 
 a source store/release signal, wherein the energy storage element in the micro-grid network stores or releases power in response to the store/release signal. 
 
     
     
       16. The method of  claim 1 , wherein recording the at least one operational constraint corresponding to each distributed energy resource includes receiving at least one operational constraint from each distributed energy resource and storing the at least one operational constraint corresponding to the distributed energy resource. 
     
     
       17. The method of  claim 1 , further comprising receiving micro-grid network topology status indicating status of switching elements in the micro-grid network, wherein generating the component control signal for each distributed energy resource of the first set comprises generating the component control signal based on the micro-grid network topology status. 
     
     
       18. The method of  claim 1 , wherein the dynamic control signal is generated for a time period shorter than a time period during which the component control signal is generated. 
     
     
       19. The method of  claim 1 , wherein at least one network disturbance signal is selected from the group consisting of:
 a signal indicating a sudden change in load demand of the micro-grid network; 
 a signal indicating a sudden change in supply from at least one distributed energy resource of the micro-grid network; and 
 a signal indicating a sudden change in environmental condition. 
 
     
     
       20. The method of  claim 1 , wherein generating the dynamic control signal comprises generating a signal selected from the group consisting of:
 a real power change signal for maintaining the frequency of the micro-grid network at a nominal value; and 
 a reactive power change signal for maintaining the voltage of the micro-grid network at a nominal value. 
 
     
     
       21. The method of  claim 1 , wherein selecting the second set of distributed energy resources comprising distributed energy resources having respective at least one operational constraint suitable to be engaged for addressing the sudden change within the network comprises:
 identifying at least one distributed energy resources from the at least one dispatchable energy resources having a corresponding at least one operational constraints suitable to be engaged for addressing the predicted change; and 
 selecting the at least one distributed energy resource in the second set. 
 
     
     
       22. A system of controlling a micro-grid network, the system comprising:
 a plurality of distributed energy resources including at least one dispatchable energy resource and at least one intermittent energy resource, wherein at least one distributed energy resource is an energy storage element and at least one of the intermittent energy resources is responsive to environmental conditions to generate power; 
 a plurality of loads coupled to the plurality of distributed energy resources; 
 a controller coupled to the plurality of distributed energy resources and the plurality of loads, the controller comprising a processor and a memory coupled to the processor, the controller further comprising a steady state control module, a dynamic control module and an adder coupled to the steady state control module and the dynamic control module, 
 
       wherein:
 the controller is configured to receive at least one operational constraint corresponding to each distributed energy resource; 
 the memory is configured to record the at least one operational constraint corresponding to each distributed energy resource; 
 the processor is configured to receive one or more system wide signals representative of a predicted change to the network, wherein the predicted change comprises an environmental condition prediction; 
 the steady state control module is configured to periodically generate, in a predetermined frequency, a component control signal for each distributed energy resource in a first set of distributed energy resources, including the energy storage element, based on the environmental condition prediction and the at least one operational constraint corresponding to the respective distributed energy resource, wherein the component control signal defines a steady state set-point for each distributed energy resource of the first set of the distributed energy resources; 
 the processor is further configured to receive one or more network disturbance signals representative of a sudden change within the network; 
 the dynamic control module is configured to select from the plurality of distributed energy resources, a second set of distributed energy resources having respective at least one operational constraints suitable to be engaged to address the sudden change within the network, the second set of distributed energy resources having at least the energy storage element and at least one other type of distributed energy resource in common with the first set of distributed energy resources; 
 the dynamic control module being further configured to dynamically generate a dynamic control signal for each distributed energy resource in the second set of distributed energy resources, based on the one or more network disturbance signals and the at least one operational constraint corresponding to the respective distributed energy resource to address the sudden change within the network, the dynamic control signal defining a set-point perturbation to the respective steady state set-points of each distributed energy resources in the second set of distributed energy resources; 
 the adder being configured to combine the steady state set-point of each distributed energy resources in the second set of distributed energy resources generated by the steady state control module with the respective set-point perturbation of each distributed energy resources in the second set of distributed energy resources generated by the dynamic control module to generate an overall control signal; and 
 the controller being further configured to maintain a voltage and a frequency of the network within a predetermined range with the overall control signal. 
 
     
     
       23. The system of  claim 22 , wherein the environmental condition prediction relates to a time period and the component control signals are generated for the time period. 
     
     
       24. The system of  claim 23 , wherein the time period is selected from the group consisting of:
 a few seconds; and 
 a percentage of a duty cycle of the energy resources. 
 
     
     
       25. The system of  claim 22 , wherein the controller is further configured to predict a load demand for the micro-grid network to provide a total predicted load demand; and wherein the steady state control module is configured to generate the component control signal for each of the first set of distributed energy resources based on the total predicted load demand for the micro-grid network. 
     
     
       26. The system of  claim 25 , wherein the load demand is predicted in part based on the at least one environmental condition variable. 
     
     
       27. The system of  claim 22 , wherein the processor is configured to receive at least one environmental condition variable and generate the environmental condition prediction based on the at least one environmental condition variable. 
     
     
       28. The system of  claim 22 , wherein the processor is further configured to predict a power generation level of intermittent energy resources in the micro-grid network based on the environmental condition prediction to provide a total predicted supply. 
     
     
       29. The system of  claim 22 , wherein the at least one network disturbance signal is selected from the group consisting of:
 a signal indicating a sudden change in load demand of the micro-grid network; 
 a signal indicating a sudden change in supply from at least one distributed energy resource of the micro-grid network; and 
 a signal indicating a sudden change in the environmental condition. 
 
     
     
       30. The system of  claim 22 , wherein the dynamic control module is configured to generate the dynamic control signal selected from the group consisting of:
 a real power change signal for maintaining frequency of the micro-grid network at a nominal value; and 
 a reactive power change signal for maintaining voltage of the micro-grid network at a nominal value.